1. Field of the Invention
The present invention relates to an apparatus and method for fabricating a semiconductor package, and more particularly, to an apparatus and method for grinding a back side of a wafer and attaching dicing tape to the back side of a wafer.
2. Description of the Related Art
Conventionally, a wafer fabrication process may use a relatively thick wafer because a wafer may be damaged during handling. The back side of the wafer may be ground to reduce the thickness of the wafer.
For example, an 8-inch diameter wafer may have an initial thickness between 730 μm and 750 μm, and a 12-inch diameter wafer may have an initial thickness between 790 μm and 800 μm. After a grinding process, the wafers may have a final thickness within the range of 50 μm to 450 μm. The final thickness may vary depending on the semiconductor product, demand of users, product characteristics, etc.
For a wafer sawing process, a dicing tape may be attached to the back side of the thinned and/or ground wafer. Conventionally, a robot arm may transfer a wafer to a dicing tape attaching apparatus, and the dicing tape attaching apparatus may attach the dicing tape to the wafer. A wafer may be provided to the dicing tape attaching apparatus while the wafer is loaded in a wafer cassette. If a wafer grinding apparatus is installed in-line with a dicing tape attaching apparatus, the wafer may be directly provided to the dicing tape attaching apparatus. The attachment of the dicing tape to the wafer may reduce a chip separation fault which may occur to the package during a wafer sawing process.
Conventionally, an in-line wafer grinding and tape attaching apparatus may include a wafer grinding apparatus and a tape attaching apparatus. The wafer grinding apparatus may include a turntable having a plurality of chuck tables installed thereon. The tape attaching apparatus may be installed near the wafer grinding apparatus and may be configured to attach a dicing tape to a back side of a wafer and/or remove a protection tape from a front side of a wafer.
Referring to FIGS. 1A and 1B, a robot arm 3 may transfer a wafer 60 between a wafer grinding apparatus and a tape attaching apparatus. For example, the robot arm 3 may adsorb the wafer 60 using a vacuum and may transfer the wafer 60 to the tape attaching apparatus.
The thinner the wafer 60 is, the more the wafer may be subject to warpage. The wafer 60 may have a front side 61 with an integrated circuit layer and a silicon layer. The thickness of the silicon layer may be reduced by a grinding process. Further, the coefficient of thermal expansion of the silicon layer may be different from that of the integrated circuit layer, and the wafer 60 may be bent toward the front side 61 of the wafer as shown in FIG. 1B.
As a result, if a robot arm 3 transfers the wafer 60 using a vacuum, the vacuum may leak through the bent portion of the wafer 60, and the connection between the robot arm 3 and the wafer my be lost. Accordingly, the wafer 60 may be dropped by the robot arm 3.
A wafer 60 may be inadvertently dropped from the robot arm 3 as described above during processes resulting in lost time and resources. For example, a wafer 60 may be inadvertently dropped during a process for loading a wafer to a wafer cassette, a process for removing a protection tape from a wafer and/or a process for attaching dicing tape to a wafer.